JPS636856B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a copying method that can freely select from positive to positive image and negative to positive image without changing the polarity of the developer and each charger, and more specifically, by selecting the applied voltage. The present invention relates to an image forming method using an intermediate recording medium in which a negative image or a positive image of a copy original can be freely selected.

The conventional copying method that allows you to freely create a positive → positive image or a negative → positive image uses developer positive, negative 2
A method in which different types of developers are prepared and the transfer polarity is changed for each transfer, and a sensitive material in which a P-type semiconductor and an N-type semiconductor are bonded, a sensitive material in which a transparent dielectric is bonded to either semiconductor, or other materials. A bipolar photoreceptor is prepared, and by switching the charging polarity between positive and negative, normal image and reversal development are performed using the same developer.
There is a method to obtain a negative←→positive image or a positive→positive image. However, the former method requires two devices, and the latter method has problems in polarity switching, positive/negative charging characteristics, image quality, cost, etc., and neither has been put into practical use.

Furthermore, in Japanese Patent Application No. 53-041303 filed by the same applicant, a specular reflection pattern or a light diffuse reflection pattern is optically selected using an intermediate storage medium that forms an image on a mirror surface and a light scattering area. A copying apparatus has been disclosed that reads out an image and obtains a negative image or a positive image. However, in this method, there is a large difference in the amount of light between the specular reflection pattern and the light diffused reflection pattern, and if the same readout light source is used, the amount of light diffused and reflected will vary. In order to make the amount of specularly reflected light the same, it is necessary to reduce the amount of specularly reflected light using a neutral density filter or diaphragm, etc., which results in a large loss of light.
This method required voltage switching in stages, and this method also had drawbacks such as not being able to obtain a large amount of light and making it difficult to form images on low-sensitivity photosensitive materials.

The purpose of the present invention is to easily obtain negative←→positive images and positive→positive images without changing the charging polarity of electrophotography, developer polarity, charging characteristics of photosensitive materials, etc. To provide a copying apparatus capable of obtaining a desired composite copy image even from originals.

Still another purpose is to read negative ←→ with a constant optical system without changing the reading method of the reading optical system.
It is an object of the present invention to provide an image reproduction method capable of obtaining a positive image and a positive to positive image.

These objects are intended to be used in a copying apparatus that receives light from an optical system to form and develop an electrostatic latent image, in which the optical system is connected to a first optical system and a second optical system that have a common imaging area. The first optical system and the second optical system are divided into two parts.
An intermediate recording plate capable of forming a light image from one or both of the optical systems is provided, and the intermediate recording medium is composed of a liquid crystal cell in which a liquid crystal layer and a photoconductive layer are arranged between transparent electrode substrates. This can be achieved by a copying apparatus further comprising means for changing the voltage between the transparent electrode substrates so as to change the state of the light irradiated part and the non-irradiated part of the liquid crystal. That is, the present invention is a copying apparatus that is equipped with an intermediate recording medium that can freely convert negative to positive and two optical systems, and is an apparatus that can easily process copied images such as image composition, correction, and deletion. .

FIG. 1 shows the structure of an intermediate recording medium used in the present invention. A memory type liquid crystal cell 100 having a sandwich structure in which a memory type liquid crystal layer 102 and a photoconductive layer 103 for writing a two-dimensional optical image are sandwiched between two transparent electrode substrates 101 is used. The liquid crystal used here is, for example, a memory type nematic-cholesteric phase transition liquid crystal obtained by mixing a nematic liquid crystal and a cholesteric liquid crystal at a ratio of about 9:1 (but not limited to this value). It is known that this mixed liquid crystal exhibits a transmittance curve with respect to bias voltage as shown in FIG. 2 by applying a suitable vertical alignment treatment agent to the surface of Nesa glass.

The present invention utilizes this electric field-transmittance characteristic, and its driving equivalent circuit is shown in FIG. In the diagram
C ₁ and R ₁ are the liquid crystal cell capacitance C component and volume resistance, C ₂ and
R ₂ is the capacitance C component and volume resistance of the photosensitive layer. _V1 ,
As shown in FIG. ₂ , V 2 and V ₃ are a voltage at which the liquid crystal does not cause an electro-optic effect, a voltage at which the electro-optic effect is maximum, and a voltage at which the transmittance is maximum.

The bias voltage applied between the electrodes 101 is V ₁ ,
By selecting either V ₂ or V ₃ , the liquid crystal layer 102 becomes transparent or opaque.

Therefore, according to the present invention, after irradiating the storage type liquid crystal cell with a light image, the bias voltages applied to the non-exposed area and the exposed area become a combination of V ₁ and V ₂ or V ₂ and V ₃ , respectively. By selecting as follows, a positive image (frontal image) or a negative image (reversed image) can be obtained.

The image forming method of the present invention performs copying using an intermediate recording liquid crystal cell having voltage (electric field)-transmittance characteristics. The second optical system consists of, for example, an enlargement copying system 2 and a same-size copying system 3, the liquid crystal cell is arranged on the optical axis of each system, and a light source 16 and a lens 18 are used to read the recorded contents formed on the liquid crystal cell. and a half mirror 17 for reading directly reflected light.

First, the image forming method of a memory type liquid crystal, which is the basic principle of the present invention, will be explained in detail. The memory type liquid crystal used here is, for example, a nematic liquid crystal.
MBBA (p-methoxybenzylidene-p'-n-butylaniline), EBBA (p-ethoxybenzylidene-p'-n-butylaniline), PEBAB (p-
A mixture of ethoxybenzylidene-p'-aminobenzonitrile) in a ratio of 50:35:15 is used, and a cholesteric liquid crystal such as COC (cholesteryl oleyl carbonate) is added to this mixture in a ratio of nematic liquid crystal to cholesteric liquid crystal of approximately 9:1. This is a memory type phase change type mixed liquid crystal mixed as 1. In this type of liquid crystal, in the initial (no load) state, the liquid crystal molecules near the electrodes of glass with electrodes, such as Nesa glass, are aligned perpendicular to the electrodes, while in the intermediate layer they are parallel to the electrodes and twisted in a spiral shape. It has an arranged planar structure. In this state, the bias voltage is less than V ₁ in Figure 2, and the optical transparency is approximately 90.
% or more. Next, when an applied voltage V ₂ is applied, the planar structure is broken and the liquid crystal molecules are aligned parallel to the electrodes, forming a focal conic structure (a unique cone-shaped structure of cholesteric liquid crystal) with the helical axis rotated by 90°. This results in a state where optical light scattering occurs. This state is maintained even after the applied voltage _V2 is removed. Furthermore, when the applied voltage reaches _V3 , the arrangement of molecules changes to a state in which all molecules are uniformly aligned perpendicular to the electrode (homeotropic structure). When voltage V ₃ is applied, the light transmittance is almost 100%, and when V ₃ is applied, the transmittance returns to the initial state (approximately 90%) several seconds after the applied voltage is removed. Utilizing this characteristic, as shown in Figure 4, the electric field applied to the liquid crystal layer of the liquid crystal cell can be set to V ₁ [V/m], V ₂ [V/m], and V ₃ [V/m]. , B, and C are irradiated onto the photosensitive layer of the liquid crystal cell. The transmittance distribution shown in Figure 4c is created from the curve in Figure 2 in the liquid crystal in the area that overlaps with the photosensitive layer corresponding to the light intensity distributions A, B, and C, and even after V _{1 to 3} are removed, this distribution remains. The state is preserved (as shown by the dotted line). Generally, documents are composed of black (or white) lines on a white background (or black background).
For example, when a positive document consisting of black lines on a white background is exposed, and the amount of reflected light on the white background is C in Figure 4a and the amount of reflected light on the black background is B, the electric field applied to the liquid crystal will be an electric field of V ₃ on the white background. If the voltage of the power supply is determined so that an electric field of V ₂ is applied to the black background, the C section of the liquid crystal becomes transparent, and the B section becomes a light scattering state. In other words, a negative image (the text portion scatters light) is formed on the liquid crystal cell.

In addition, a negative film image in which the character part is transparent (part B) and the background part is opaque (part C) is
Exposure is performed using transmitted light from an enlarged copying system as shown in figure 2, and the electric field applied to the liquid crystal layer is changed depending on the amount of light in the transparent part B.
V ₂ , and by determining the V value of the power supply so that the electric field applied to the molten crystal layer becomes V ₁ depending on the amount of light in the opaque area C,
The B part (character part) of the liquid crystal becomes a light scattering state, and the C part (background part) becomes a transparent state, forming a negative image on the liquid crystal cell.

To explain according to a specific example, the Nesa glass used here is made by vacuum sputtering an In ₂ O ₃ transparent electrode with a thickness of about 1000 Å on a thin glass plate and heat oxidation, and the photosensitive layer is made of As ₂ Se ₃ with a thickness of about 1000 Å. The liquid crystal layer was vacuum-deposited to a thickness of 2 μm, and the liquid crystal layer was vacuum-inhaled to a thickness of about 12 μm from the nematic-cholesteric phase transition liquid crystal mentioned above, and a thin film of about 3000 Å thick was dip-coated with an alignment agent lecithin for alignment treatment. It is a type liquid crystal cell. Using this liquid crystal cell, bright areas of images can be
When the light intensity was determined to be 100 lux and an image was written, a negative image was obtained from the above-mentioned positive document on the liquid crystal cell with a power supply voltage of about 60V, and a negative image was obtained on the liquid crystal cell with a power supply voltage of about 45V. A negative image was obtained on the liquid crystal cell.

The copying apparatus of the present invention can, for example, print micro-enlarged negatives →
It is a dual-function copying machine that has a common electrophotographic mechanism among the mechanisms of a positive copying machine and a same-size positive → positive copying machine, and the image is applied as an intermediate recording medium on the common optical axis of both copying systems. By controlling the voltage, we have placed a device that can produce a negative image (light scattering in the text) regardless of whether the original image is negative or positive.
A reading optical system is provided to read the recorded image by directly reflecting light.

The apparatus used in the method of the present invention will be explained with reference to FIG. 5. In the enlarging optical system 2, a subject film 12 is projected by a projector 11, and the light image passes through a lens 13 and is reflected by a mirror 14. Then, the contents of the film 12 are recorded as a negative image on the memory type liquid crystal cell 15 by the method described above. The surface of the photoreceptor 6 of the memory type liquid crystal cell has a metal surface when viewed from the light source 16 side. The content recorded in the storage type liquid crystal cell is reflected by the light from the reading light source 16 onto the half mirror 17 to illuminate the liquid crystal cell, and the reflected light is transmitted through the half mirror 17 and projected onto the photoreceptor 6 by the reading lens 18. be done.
When projecting an image using directly reflected light in this way, the image recorded as a negative image on the liquid crystal cell as described above will cause light scattering in the image area as shown in FIG. The other parts are directly reflected by the mirror surface of the photoconductive layer 103, and the sixth part is reflected on the photoreceptor 6 of the copying machine.
The light amount distribution is as shown in Figure b. In addition, if the cloudy part (light scattering part) has a certain degree of directionality, such as in liquid crystal, it is naturally possible to use a method of irradiating oblique light with a lens system as shown in Figure 7 and using the directly reflected light. . The light irradiation angle θ at this time is an angle determined by the cell substrate, the Nesa film, the scattering anisotropy of the liquid crystal, etc., but good results were obtained with an angle of 45° or more.
Further, the opaque original 20 placed on the platen is illuminated by the light source 19, and the reflected light is reflected by the mirror 5c,
The contents of the opaque original are projected onto the intermediate recording medium 15 consisting of a liquid crystal cell through the lens 4 and the mirror 5b (dashed line) (if the opaque original is negative) and recorded, and the contents are further transferred onto the photoreceptor 6 using the method described above. The image is then projected, developed, transferred, and fixed. in this case,
Regardless of whether the subject is negative or positive, it is usually recorded as a negative image (the text is opaque) on the intermediate recording medium, but it is also possible to record it as a positive image (the text is transparent). When is positive, the reflected light passes through the mirror 5c, the lens 4, and the mirror 5a (broken line), and is directly projected onto the photoreceptor 6 without passing through an intermediate recording medium, forming a latent image, and performing the normal xerographic process. It can also be operated like a normal copying machine to obtain hard copies.

Further, according to the present invention, in the device, since writing can be performed on the intermediate recording medium from the enlarging optical system 2 and the same-magnification or reduction optical system 3, overlapping copying of two or more objects is possible, and image correction, compounding, etc. It can be applied to a wide range of applications.

As described above, according to the present invention, regardless of whether the original image is positive or negative, a negative image (or a positive image if the copying mechanism is for negatives) can be recorded on the intermediate recording medium, so that reading can be performed using specularly reflected light. This makes it possible to reduce the amount of readout light.

Furthermore, since positive images can be easily obtained from negative or positive films, or from positive or negative opaque documents, positive images can be obtained by combining, for example, a microprinter and a full-size printer in the same system. It is possible to design a micro/opaque printer like this.

Furthermore, it is also possible to record the film image and the contents of the opaque document in a superimposed manner.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the structure of a storage type liquid crystal cell which is an intermediate recording medium used in the present invention, FIG. 2 is a diagram showing the applied voltage versus transmittance curve of the storage type liquid crystal cell, and FIG. is a drive equivalent circuit diagram of a liquid crystal cell, FIGS. 4a, b, and c are diagrams showing the electric field distribution b of the liquid crystal cell and its light scattering degree (transmittance) c with respect to the amount of light a, and FIG. FIG. 6a is a diagram showing a state in which an image on an intermediate recording medium is directly read by reflected light, and FIG. 6b is a diagram showing the light amount distribution at that time. , FIG. 7 is a diagram showing another state of reading the image on the intermediate recording medium. Codes in the figure: 1...Copy machine, 2...Enlarged copy system,
3... Same-magnification copying system, 4... Same-magnification lens, 5... Mirror, 6... Photoreceptor, 7... Charged corotron, 8
...Developer, 9...Transfer corotron, 10...Transfer paper, 11...Projector, 12...Film, 13...Projector lens, 14...Mirror, 15...Intermediate recording medium, 16...Reader Light source, 17... Half mirror, 18... Reading lens, 19... Reading light source, 20... Opaque document, 21... Collimating lens, 22
...Screen, 100...Liquid crystal cell, 101...
...Transparent electrode substrate, 102...Liquid crystal layer, 103...
Photoconductive layer.

Claims (1)

[Claims] 1 Forms an electrostatic latent image by receiving light from the optical system,
In a developing copying apparatus, the optical system is divided into a first optical system and a second optical system that have a common imaging area, and either one of the first optical system and the second optical system is selected. and an intermediate recording medium capable of forming a light image from both, the intermediate recording medium is composed of a liquid crystal cell in which a liquid crystal layer and a photoconductive layer are arranged between transparent electrode substrates, and further includes a liquid crystal cell capable of forming a light image from the liquid crystal. A copying apparatus comprising means for changing the voltage between the transparent electrode substrates so as to change the state of the transparent electrode substrate and the non-irradiated area.